SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d4f3e4c610c3bd01bfb6967cb744615c0e0d06b5492136c367d2271cf57200e' 
  AND token = 'KUHXGYO2x5AVQnZfRlr/ipsZKSRu71OcTeOJsMARzgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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