SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c1751a4a7f009fe72f2f20bbb13dbdb1cbcf58f922f797614846a7e7e921fb51' 
  AND token = 'iHGNsaognlktGBTikiWxZ78pkOZwYylROJOc0h3Nd3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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