SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c550293ae128d0fc8addc4d33ef57c4986918b48816574aa26797be53e1a27fb' 
  AND token = 'lnFzqXclNfIfkuZtfgYoPHFaXFX6eJzGPDlM2Zd+pfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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