SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '311302b688c4a203134f25823b6a5519c85b93cc2ffb5b4df9c5480f7a9d264c' 
  AND token = 'JMP9aOoieYnpD9mm0dVYJpCIaTpMzim8HQIwFuCFdw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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