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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e8119382abec2bcbc3778db1b3df0c406e5f65bb88731e695d8e75a164e9a2a7' 
  AND token = 'Zeg2RvTiDmJEHQlbR/WE0WRTglaVXC2Lyu2qMM+6Q+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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