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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2b7b8506fc471befe270cab499c93d26e5f0d8aade818c05ff3a23ed55bdf27' 
  AND token = 'egbf2E7T0QI+Rr6WDat2sCk2Zbk/VeuouIYoCwEeW3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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