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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '937b7087c996d18342261136235b36f0315dbd93abb3890897977f1235f90dab' 
  AND token = '6DaY+TcSE+3wgtKslLJs8wQ1WE+3kiqVBY2xctESCeM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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