SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46b336c8fb936c8432bd8d628b5087fda4d4bcae35d3c1f59359575b626a5a51' 
  AND token = 'uRRJRA3nPU2PBW1Vwl/tM98EHUYch+OvtB87+09YSiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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