SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cff10c12892317e79ce8a606b1b1f13ede0714df6b79e740cfbbf24508875343' 
  AND token = 'Qv/Ee5ZRB2o+mGlbqD9SYdlGKPI3CGPDNmjkRYVJAQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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