SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2fa0e7562235fb491e80407c6a9e5fb17a776a6edfda0feeac7d82105132e5eb' 
  AND token = '5txpPMnfrCHfat+CdTX15V0dNrzGd1Qm6otgqbQNi/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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