SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '965eb48c4d03618971cc090993c2bc25332ad036cc936da63a8468daa267ccbc' 
  AND token = 'tMYvO+ruFG7EgQz3qsElWfhkXEMH5WDNlwaUl/Dq2Oo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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