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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e9caa8b2e2b10b967a62e103eca71841ddcb2a3d13ea52a0ee584a7a6fb9123f' 
  AND token = 'JeB2BGN9WkmhwQJNpgwK7EH/Krwe5XfYponWzhECkrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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