SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ac8e56494ff4a34d06662865e14a72d1c03f9830d829600653efc1c5bc25c5d' 
  AND token = 'qZFekVANGw1goYlxb3OE6evMRFeU+lscCT2iWnZgiSA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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