SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46c35b12e79d4a866aefa4b2cbcf34758db90d4ea12f90d738b860d689e7562d' 
  AND token = 'oXm/4gJIJHErwhHHcHyS4AKgUnfz3PnaTuJCAaxfyBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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