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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57ab3bfb9bf8e2ca38cdd7ee3cd0963dae7fc2b23a6ded2fcd69db49854ee314' 
  AND token = 'uaPsgqyDw7WWzUBsnWzawsKzZ0UHejf8rKSQERfP+gM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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