SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd21fa59dfacb732ae58f32febf6330064c6d326ac8aacdc2654e14a7f586d9b' 
  AND token = 'CoUD5i3ieNoCUnjJ+DPSHT8NGTi3xxr77rxJWJHeWnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}