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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd94e99547e6fa43fe8a6d8d1d9b9bd87af1945f2cd6723f2ead58ed1c44c6edb' 
  AND token = '6oc1WLBNeHN9mzeEQ00eAPgmtTRzr2v9Psv/FC/Tfm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}