SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c32e921af21126439b35281f9d776109b31404180a9521eb58411c389df48aca' 
  AND token = 'IBtgRcUcp/zYYkz55IF+GFEXMq6nipUcIqD874zHH9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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