SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '876d1e7cb6908b8dbcdacb6b45886fdcf6f70c28a19ed14b5c7cd2479bc5ee45' 
  AND token = 'ZWKrgfMdcGOztPGJK2q3ojmK6LLiu5ArvpnwjLoAhfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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