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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1248b57ae5f8eb8aac13342178c66df9baca879676d05e3dfca8f59bece4b43' 
  AND token = '64jQPkPq9wV4m4zhFO2f5qfqkC+/bdI7uvqV2YqDy1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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