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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '11a35001d77ca4e00b0cae797f6e2e1056d8a1ac7a6b1c1122a1d8386f0c74c1' 
  AND token = 'gKFny3VoRyX8pF/7cAWLBzGee64aPRwhXYLkFDLeijc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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