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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a5ea9fcbeaea25a09f1536df47e337e49e8b89bfb8a2bd35c399ea14a7f09fe' 
  AND token = 'PiG9i8+XvnuBA/9c5x7W7oP43+HFLw4ujUmn2CM2/7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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