SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53a58357cad89b4df0df24d36d1425f0a36fae6079755c3c1fb66ed97cc4c53b' 
  AND token = '+4TBcZoauruOLCRr85tGT4zEJ+6b/mteXoZvlvOujq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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