SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5fe71c44218fb459ecf766ff8bc93bfbe939934062ab73d895325dbe24c354a6' 
  AND token = 'G1a75VC0CLLjdD7iXarvjWtLiQhuH/z++rtyilOJDZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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