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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ff1656d2b9f5fbd74d7db27db840faf5e31aef527fdcd59db3f5f7994971c9b3' 
  AND token = 'hyzZ/8mmAvIrC3XsEMeJ9zbWrG6HN/P5S4iNl85rV6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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