SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25e1e344201e7977da003c7d4570f9fa08db0be37682bceed475f973ecbfd505' 
  AND token = 'ePiMXKso6Oft+2PyH2MBlsjzuuo3z5Cz2C7s807XbbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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