SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d3b3d40931ebde478b3f02ea3aedad32f6e8d4f651f75c2079d578f0dd2b132' 
  AND token = 'mUKafh1SgA6EoXCzkThislQTmw1/eoVxaoOp/IT42g4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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