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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0da3d6516b566f7e2cf0e29a17f2b2d4a1cc9cb72120031ac02d99c26722a40' 
  AND token = '1DdcaykfHALIfFqnq/Oj+Mp/UrLEeLUbuqmWv/fQQbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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