SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c19bbcafb6531f16f5f3a3e2e42545edb40f9d86ff76902abdaa3408cca8965' 
  AND token = 'QwyT7hyASXS08CDQoFHCgTQsCSlIUYvs0fkOqDWoYSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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