SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '383ce10f5ccd3bd04680018580dce2f1e995f19291d2d1f43e85594f0d38adec' 
  AND token = 'QeemyfGloddBE8neCzToLF5qdMSFyDSD6EsYdfHg57E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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