SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '42b968dbe013fe859843e0860c18cdbf0dc89c5bd1531f09233bbf39def716c8' 
  AND token = 'chi7DHgPTwCPsAITszrBhWVrU3da3lnTqndONrct2NU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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