SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '268b6f6f22e84625bf92aa01a5cb487ec5d464b97be3207a8ae2a452f9aa7aa9' 
  AND token = 'X2n/6XjvdgInAsVohalhbUCBBddROMil3G+ILhN4vFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}