SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '744bf4f22efc28ff170b712912649ebf9a0bbd00c6f00d550a3d2615d7184cdc' 
  AND token = '309j7eYlfPTbeK60POpoR2j62n6pgPfyjkr4XnAAICY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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