SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92801a9f78550652d073a2a2b8d682f13c7d4d06b1ba64a884fd1306c6b1a149' 
  AND token = 'kvAmqbcxR3p2Lx6BKtTrpSC4OPEcT1pcps9rvM3lVt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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