SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12c640d3885c7ebfdff21c17b1cbe6ffc8a5035779049aa222ebee16264bbed3' 
  AND token = 'SkqoNUV9CqhEsaPhCs1lFvZ5jIi/pKIJBBCRwVJoNYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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