SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b245205aa8cb6162c8416e7c22e438c392fcd0b5c7a697bef73b555d031843d1' 
  AND token = '8L1vwnSEUEq3IBK46fSEb346keoJ7Cvw12/P+1pX16U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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