SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4f510a7e6580f88b889dbafd413d89fb0a0282ccf668d3cb9426a2c2b6a8320' 
  AND token = 'yFqpPchPId38TWw7pkk6F7FKSsTXCYxGNCNY2jOhZVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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