SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd373c846ae68dc5c2b76faa85f9dab037569a3885e0529239a5d609ed0212a8' 
  AND token = '8Q/Ffh4ezS8NNiCp2+rtwJ3JNUPXbcjVDW03BHysqkI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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