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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd24a437bcb9b45ded62bb507e27c9e5d0ad6ab852d262e5d7fbb3f76d47a958a' 
  AND token = 'LhuzPQv/FnTD+Axb92/Dv712/vVTSe4UNAawwb8Dcjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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