SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b00d0827d6490634743f152aa3736e31d2ef6e0a18cba775bd9fcea242ee8b33' 
  AND token = 'pWwazQWLDD33uZg04mbnQTokdll/rGZyA4mzroRmITI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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