SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7a5586f3a1d140d75b3cbd2830252a0bc0835ae228c15d23d3a033451a836403' 
  AND token = 'meaCoaWOfwuYUX4OHfpNdRHv4xMSddzrlpPEsWkFMq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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