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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5b680e01c6be42dc6a270ae19a676c11fd0b708ae7404068c6bdc7a26890cb4' 
  AND token = 'T9v1ooZQtOezgP9ZDcQi3QwEZTSWbrAPRQZpmgqDQkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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