SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6494ddd3263912e37c305d1a27f2d36e473216a5ee2b758b5f1e989f27447c92' 
  AND token = 'R4w4MuqJOPV2laQDM3bSZRgIHLkyZ1GpnKTJU0UQmjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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