SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2febb6ddb9848bd85b72515202890686e3124652779c7d3d3e02e99b98f79957' 
  AND token = 'pZlTHVGzzca5ZzaqmJH2xS1A6Nay2ROjorda3uXqnC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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