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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '50f52310f1b86b63a6efbd27dbfb1ebb2d0245f0b4e9a14f00eee2cc57980739' 
  AND token = 'ZV8G1EdGRJdPoE2vrxE/VQd1OoKMYnbuOyJWIaQ+M7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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