SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83b720685a3fd8dd7211df01aa4cab905d3c4c19fbf0ccf0b5c85fc7d256df5a' 
  AND token = 'uzQwgMFpk/SwWBU4rT7PlLtzIA3+w/bl5weJiSnEMXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}