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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '978a9649fef6813e9674f6e73a8827e79be5f7f475fc61d17ce6b8e2ca735cb1' 
  AND token = 'z0zxV8XsuNwZ+N0kVKSw2YtgK0esKWT9JKAVpga02lQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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