SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66376e602fa214f9fd22fd09ca59ed89db88511bbfdb7f9a1103f7670016c8c0' 
  AND token = 'XNqhT2XpcyQipRX0aUaxHfiL9imKFTWNpvFQpL9WjQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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