SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa6698abf23ba29877fb9dfba3acbf11172e9146a09aa0349cdf095281029075' 
  AND token = 'vSdHokha+gsHhH673LmuosedVSPCObMneC5RC0LqfnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}