SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9374ba36ff0e78f87324a085d72c483cee749fdd14fd586fd9a769cb069caa28' 
  AND token = '6awaS51Prc1rZPhh3sTdBf6Fh9hBABskb1ezwRMmeS8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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