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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '351d50fdeaf79ea91e0abe7af5b2f07790b40dde8f655ea7cc7cfd2ae2c44a4e' 
  AND token = 'nIjExxfRH/YDyQZSnLpNqzqGJ7L3tKxuXhuKh8YxHcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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