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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2e206b02f33f5c300a6721e1c72bd07edf3ad1757fdb501604b862f610a3ec23' 
  AND token = 'VY324dxkZp0MFQhTWUc+zqXa6A7sFUZjArIyzTPH/mU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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