SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '759dafe088c47fbe31051d36e84d8d9eaf1bb7a86a8898c1ee2d7a77ac5aa726' 
  AND token = 'GCnBrCcjz0Lt8RTugzcxsZhwE/JBhmQwHdSqEmIz2GA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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