SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31345b31338032eca85992b2b1c1007756b5e233b3c6c6748221cedd961ebe8a' 
  AND token = 'vcOOMt5hO9bJFDi2VU6ULxvE5IWACFNenp42kFHkM7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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