SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3f4324ec9d405fdc12a14630af998e3d1ec6edab8e582ffeb3b6005e48590c2' 
  AND token = 'aConnaFPrlqvl9mbnDbqKiZua//z47xbfy/GpLGBr9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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