SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6bbbb0866321546a10766b62aa339d51d2b658391865446643f0ccbb8ad9d16' 
  AND token = '4EYEonPyEaKGXI3HIT4sBF1RLcwzYIW4M70ZVSaufDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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