SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6a9c6d60f32f9e82e4f32b353f131677d4f870553bd9640abaeadc0202cf4b6' 
  AND token = 'WBIKGhljy87gYef4NvvSPZlPhbg1PnszB8pM0q3TKl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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