SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c75e998972ec54b8071bb1d4c88baaef1e92df53b540324384cdf97dda8012f' 
  AND token = 'eF/NjQ3b3yWYovLdW7WX2mGusA5DeBWbXzC1Ab9uYKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}