SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16040389b7173049a54ce4eb7ed61174124d3775f6ca42be7e8e6ac76cb59b42' 
  AND token = 'zlNf/Ek475s1qx9TeOcqbkNT3NoV1pcIelNoJdMpFio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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