SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e4c3f3843a37daf67c09d20898d68fd25a33119d92ee7bd31771706ede91391' 
  AND token = 'ZLsr/CWR32rd2rKCdivs2R1k+nN2R6C9lT/Hg15bpYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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