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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '68a8ec7fdc9e37526a62b967a60bcdc18e3dfbe5a556a4def428d2a0f1a926dd' 
  AND token = 'K+q7NoO9iJHApIqX8PRpEUkl/NDnaG7T8PsH8gOGRow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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