SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '758a3e0f92e3ab87c14d2c22b6b8abc1ef5390da54bb3bd28653ab715a0ea496' 
  AND token = '/jju+eugwMUxRPy4Ex9bkJlBGmA4LCvT5P7MgvLK76A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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