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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c851a87cc7c1f37f68430651752c4157ea365fdb900e64cedd1d62032a5c4d0' 
  AND token = '8WaJkF69/8ZKgeRZKfxCcCMPHStdmfyQk4mi5jujBew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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