SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c187c6d2efc0548c77163212b990c17059a23c0afb9b5a282e6e8811fa304e' 
  AND token = 'QrjePPWDQSMCCHP8TWw40R1yHp9OqOl6DZwRmzcRlEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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