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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e126c8cf614c3df48ab7decfde7abedb5eca4d54d8fccc1136c4bdf731a1a5df' 
  AND token = 'm7ZzZupfTHXoTUcibV5BB+5EGCZ1lsyu+XCGQtS0ClU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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