SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0236522957937d8317a9440c61b94f86bdd660492be372d41d8ee9e74a23798' 
  AND token = 'emF1aWkh16P0ZN89EeCifpJgf/z3Ux6XxqbDRHMZMrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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