SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57d75e7fc7c1b77fb38596379d6088dbc7bd459bd7e20f3d8bbaa4d609f91fe6' 
  AND token = '5ppuF1xuNaJcg9TWaAlHq9szT0KficAUmjr3vW7H+H0=' 
  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"
    }
  }
}