SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8c3b2859f94c489a0b865cc47fc850047555743b12b37970ee50e438eac64173' 
  AND token = '1mKOVVjg0lC5AD/yCFTVMLyWRm4TkOV3nnVm8GC3dG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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