SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1d90407d8ebdff88ab38625c3275309431c6e5f2a0fcb114071824402fdcae4' 
  AND token = 'zIdh2HGkiasgMjmrk6LqtdVIhzmHGdwU7pGzWtVgcXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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