SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c52f934e44aa7c75fe0ece735c9b962ce4f01adc63a3f39202564ad3132badda' 
  AND token = 'ldcCOdwHnOh78LPxvAB12SSPFujVfKhk/09fNtZzMEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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