SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a45c1683a85a0366d856bfcf675ff9658228d4f391993e3550eb7a1d72743ea1' 
  AND token = '1YSO/G3kONMsnTHateRZo0MwQ+kL2RDS5Aicds1VOZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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