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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'be4142fdcfaac1b4b5767fab8fb480f0d3ebc059eb7d1f4558a6f100ccda3d1e' 
  AND token = 'JadMJFUXrcxN2P1V3uuk82ud0lfzEEcOKJ5kzGYQtIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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