SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b823229a19c386a396badcdf55acfe198f01ddf919298e95d887e145c23701e' 
  AND token = 'eVLF+hgH5JtwKuZ7Qz0cNkENa7aNQ4RWQeqg5XE0xKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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