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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b52d2f70daf94480ff450894cf4e12fca70ced2a7a94481004f8b3e3fa8c338a' 
  AND token = '+ECVIMTnjh9Z1iz6ZtsFk63eu/u4vkFGZS8yvqAYHdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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