SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '50589bf6459bfc206285a7a38b840834efba187e256bff18fb3a408868484aa2' 
  AND token = 'O3Fdk8jOj8nXBKBiKhxmiwQlZ6ex5lCG69RjxNmzQko=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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