SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '391a737e74075b6b33de9471da3afaeb63456659d841b13d33d94396df7a47a1' 
  AND token = 'cDXYvslC93zk9j3jjNXxvHl9tma0XcPJz4+QBme0PMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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