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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e1ec0ef19c9ce97fc7e39e321efa5dc930ee3eaf2faf22e8db09a0a1b81092c' 
  AND token = 'KYJQ2oXiOAHz/RjX9OMNyyhnJCFJjKUNcmN+bvFprIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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