SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62bdfa1eee8e1d4aac9fb597fa4ca1cd2a7a2bafc916ffb46639b226ba051ee5' 
  AND token = 'srneYUL+vJ1KxiGjctwWKQNBlyxkjOXY49s2PdQutyU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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