SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93843bd60d7820d2bcc1381d458f531111c3870a2553dee2df3c7996a520a2d5' 
  AND token = 'jGxFaAA9oCpLbgrUpIUETfjeii35N3EKmMVykauHt5w=' 
  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"
    }
  }
}