SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '896a04b27ca4a1263ad4487b7c2b7340edcf026f87a0735cb66b8d937c6ee6a2' 
  AND token = 'VS/C3UkEPgmWnhIMay5+6nRWF2GZzDPsDbSt6Nfqkdk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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