SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76432afa5270430bb834b1f9ab684e971b90dcf349338d339d9f92282403929a' 
  AND token = 'NMsJsoUVvw6uIPPXu9CWSzH/1HxFzv6iMJ/5tDZg8bY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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