SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e2945f5a0e5616706c77858358f15c42070b802da05cb8f2671a8908476aa65' 
  AND token = 'oWqHNpvn+M0he0fBUYWnjG1y0gHQ8TPbF9A+ubKehdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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