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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8489dad64fcd28898101347d9ba06b786b245d20895fbb5cc99e8aa2b1a75f2' 
  AND token = 'f/6il+rAWl0QwHyvH/e/++W1WEA22I8dWzaEE5UUjV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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