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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a0093e4785f10cec447ed442f732071e66e57c83d907ec1b2f5fc4ea96f7f41' 
  AND token = '4L8iXrpUgEodXfjfIzpyqc8dYFDOKYSxSdkXQMGycGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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