SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19419293fa90f8928dc3b56fae80a0abe055f15408701c5d7c9eba14634772dd' 
  AND token = 'W7iaONVrV36oT92/sS+NbstjHakHstLiFXMMTnLXISs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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